Because optical fibers are fragile and easily broken, the optical fibers are usually coated with a protective coating system, for instance with a soft “cushioning” primary coating that is in contact with the fiber and with a relatively hard secondary coating surrounding the primary coating. In addition, the coating system may be used to reduce attenuation, i.e. the loss of optical power as light travels down a fiber, as a result of microbending of the fiber. Providing such coatings should however not be at the expense of the cure speed of coating compositions, as this would limit line speeds in fiber drawing and therewith increase overall production costs. Accordingly, one of the objects of the present invention is to provide a coated optical fiber having a primary coating and a secondary coating, wherein the primary coating has a high cure speed and provides good microbending resistance.
U.S. applications Ser. Nos. 09/989,703; 09/717,377; and U.S. Pat. No. 6,528,553 discuss primary coatings and microbending. All three documents are hereby incorporated in their entirety by reference.